and some, as noted by the minimum numbers,
were extremely low. In fact, these lowest samples could not likely be considered to be true
colostrum. Calves fed 4 quarts of this lowestquality colostrum would not be able to attain
adequate immune protection.
Past studies have shown that as first milking colostrum volume goes up, colostrum quality falls on average. A good thumb rule is that
if a cow gives more than 15 pounds of first colostrum (provided she is completely milked),
there is a good probability that the quality
will be marginal or low. Cows with higher genetic potential for milk production secrete
more milk and likely increase secretion faster once calving has occurred. Cows that leak
substantially or are milked prior to calving
have lost much of the value of their true colostrum with this pre-milking or leaking.
In addition, delayed first milking causes lower
IgG levels in colostrum. The drop in IgG as time
What’s in colostrum
these days?
“With today’s heifer feeding programs,
vaccination programs, and management, heifers and older cows have
nearly equal colostrum IgG levels.”
Quality hasn’t changed much in four decades. However, IgG levels
are trending downward while mineral and vitamin levels are higher.
by Jud Heinrichs and Coleen Jones
HOARD’S DAIRYMAN
C
692
ALF colostrum is the all-important
first feed for the calf that allows the
calf to be healthy and begin to grow.
It provides much needed nutrients
and, most importantly, maternal antibodies
that protect calves from disease.
Penn State has been conducting a series of
studies related to colostrum. Funding for this
applied research has been supported by the
Animal Health Commission of the Pennsylvania Department of Agriculture. With the
exception of immunoglobulin concentrations,
it has been many years since colostrum composition has been studied. Over time, changes
in genetics, management, and nutrition may
have impacted what is currently found in Holstein colostrum, so we set out to see what is in
colostrum today.
We visited farms in four major dairy areas in
Pennsylvania and collected colostrum samples
from Holstein cows. The first components measured were fat, protein, lactose, and total solids.
Our analysis showed some relatively standard
values, similar to the ones reported 40 years
ago (see table). While the average looked good,
the range of samples was very wide.
Clearly, many samples contained adequate
to exceptional levels of nutrients, but when
you look at how poor some of the samples
were, as shown by the minimum values, you
see a different story. The lowest samples that
we analyzed were so poor that calves receiving those colostrum samples as a first feeding
could not have obtained enough nutrients to
get them off to a good start. Although there
are some cows that produce so much firstmilking colostrum that nutrient concentrations are diluted, milking the cow as soon as
possible after calving is very important to
obtain colostrum with the highest nutrient
levels possible. Collect colostrum within two
The authors are a professor and research associate in the department of dairy and animal science at Penn State and wish to
acknowledge the contributions of graduate students Sylvia Kehoe
and Meghan Moody in completing the research described here.
hours of calving for the best results.
Mineral and some vitamin levels were noticeably higher in these colostrum samples,
as compared to studies reported 20 or more
years ago, which likely reflects more attention
to feeding dry cow minerals now than in years
past. Minerals and vitamins fed to dry cows
directly impact colostrum, and many of these
minerals and vitamins are quite adequate today, making supplemental injections for new-
“Mineral and some vitamin levels
were noticeably higher in these colostrum samples, as compared to
studies reported 20 or more years
ago, which likely reflects more attention to feeding dry cow minerals
now than in years past.”
born calves unnecessary in many cases.
Another very important component of colostrum is its immunoglobulin content. This aspect of our samples was more disturbing. Values ranged widely, but the greater concern is
that the total immunoglobulin concentration
of the samples was 47 mg/mL (to get the total,
simply add the amount of IgG, IgA, and IgM).
Generally, 50 mg/mL is considered the cutoff
point for good versus marginal colostrum. So,
on average, our samples showed colostrum
immunoglobulin was marginal. While some
samples were very high and more than adequate, there were as many that were too low,
Colostrum composition in a Pennsylvania survey
Fat (%)
Protein
Lactose
Total solids
IgG (mg/mL)
IgA
IgM
Average
Minimum
Maximum
6.7
14.9
2.5
27.6
41.0
1.7
4.3
2.0
7.1
1.2
18.3
14.5
0.5
1.1
26.5
22.6
5.2
43.3
94.8
4.4
21.0
to collecting colostrum increases may be due to
re-absorption of immunoglobulins by the cow,
dilution of IgG as the amount of milk secreted
increases, or a combination of these factors.
Another component of this study was to look
at the bacteriological status of the colostrum
samples. We found that nearly 30 percent of
the samples had standard plate counts greater
than those generally considered a standard for
quality raw milk (less than or equal to 5,000
cfu/mL). Since we really do not have standards
for colostrum, those used for raw milk are suggested as a starting point for comparison.
Our samples tell us that some farms have
room for improvement in their collection of colostrum. Whether it means more attention to
cleaning the udder and teats prior to milking,
regular cleaning and sanitizing of colostrum
milkers and collection buckets, or storing colostrum in ways that limit bacterial growth,
better colostrum collection practices can help
reduce the number of bacteria in colostrum
and limit the number of potentially harmful
bacteria fed to newborn calves.
In another related study, we wanted to see if
the traditional understanding that heifers have
poorer colostrum than older cows was still true.
For that study, we used four larger farms and
analyzed colostrum from every cow that calved
during a four-month period. What we found was
that, with today’s heifer feeding programs, vaccination programs, and management, heifers
and older cows have nearly equal colostrum IgG
levels. This means there is no need to arbitrarily discard heifer-produced colostrum. Heifer
colostrum should be treated like cow colostrum
and fed when it meets your criteria which may
increase the colostrum supply.
While older cows will often have more diversity of antibodies in their colostrum, many of
these older cows produce so much more colostrum that the additional volume dilutes the concentration of immunoglobulins. We found that
some heifers actually had higher colostrum immunoglobulin concentrations than older cows.
Many aspects of colostrum management are
not new and have not changed drastically;
however, we continually see mortality and
morbidity rates at the same levels that were
found 15 to 20 years ago. One of the definite
reasons that we are not seeing these levels go
down as we should is colostrum quality and
colostrum management practices are not improving as they should. Many of these can be
fixed with small changes in management of
the newborn and just-fresh cow.
October 25, 2010
Used by permission from the October 25, 2010, issue of Hoard’s Dairyman.
Copyright 2010 by W.D. Hoard & Sons Company, Fort Atkinson, Wisconsin.